US4613209AExpiredUtility

Smectic liquid crystals

Assignee: AT & T BELL LABPriority: Mar 23, 1982Filed: Mar 23, 1982Granted: Sep 23, 1986

Est. expiryMar 23, 2002(expired)· nominal 20-yr term from priority

Inventors:John William Goodby Thomas M. Leslie

C09K 2019/325C09K 19/28C09K 19/322C09K 19/24C09K 19/2021C09K 19/02

PatentIndex Score

140

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Claims

Abstract

The use of a certain class of liquid crystal materials that exhibit a smectic C phase allows the production of a bistable liquid crystal display element. Such bistable display elements promote the use of matrix addressing for liquid crystal based elements in a display.

Claims

exact text as granted — not AI-modified

What is claimed is:

1. A display comprising (1) a liquid crystal material, (2) a plurality of electrodes suitable for applying a voltage to said liquid crystal material, (3) electronic means for applying a voltage to a desired electrode, and (4) means for producing an observable optical change upon application of an appropriate voltage, wherein said liquid crystal comprises a liquid crystal in the smectic C phase characterized in that said liquid crystal material comprises a compound represented by the formula ##STR79## where Q is a core entity that comprises a moiety chosen from the group consisting of ##STR80## then Z is H, or CH 3 , where A provides a separation between Q and C a which is at least 2.0 Å, and where C a is an appropriate asymmetric carbon atom whose asymmetry is produced by an appropriate choice of R 1 and R 2 .

2. The display of claim 1 wherein Q is the entity represented by the formula ##STR81##

3. The display of claim 1 or 2 wherein R 1 and R 2 are lower alkyl moieties.

4. The display of claim 1 wherein said electrode comprises indium oxide.

5. The display of claim 1 or 2 wherein n is in the range 7 to 16 and m is in the range 2 to 10.

6. The display of claim 1 wherein A is a methylene group.

7. The display of claim 1 wherein said liquid crystal material comprises a compound represented by the formula ##STR82##

8. The display of claim 1 wherein said means for producing an observable optical change comprises crossed polarizers.

9. A display comprising a liquid crystal material in the smectic C phase contacting an electrode characterized in that said liquid crystal material comprises a compound represented by the formula ##STR83## where Q is a core entity that comprises a moiety chosen from the group consisting of ##STR84## then Z is H, or CH 3 , where A provides a separation between Q and C a which is at least 2.0 Å, and where C a is an asymmetric carbon atom whose asymmetry is produced by an appropriate choice of R 1 and R 2 .

10. The display of claim 9 wherein Q is the entity represented by the formula ##STR85##

11. The display of claim 9 or 10 wherein R 1 and R 2 are lower alkyl moieties.

12. The display of claim 9 or 10 wherein n is in the range 7 to 16 and m is in the range 2 to 10.

13. The display of claim 9 wherein A is a methylene group.

14. The display of claim 9 wherein said liquid crystal material comprises a compound represented by the formula ##STR86##

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